FIGS. 1A and 1B are left (driver side) and right (passenger side) elevation views, respectively, of a conventional semi-trailer T′ adapted to be connected to and pulled by a conventional tractor/truck vehicle (not shown). The trailer comprises a forward end or forward region FT and a rear end or rear region RT spaced-apart from each other on a centrally located longitudinal axis L. FIG. 2A is a partial plan view and FIG. 2B is a cross section view of the trailer T as taken along view lines A-A and B-B of FIG. 1A, respectively.
The trailer T′ comprises a cargo-supporting platform P including left and right laterally spaced-apart edges or sides LP,RP (see FIGS. 2A & 2B) that extend parallel to each other and parallel to the central longitudinal axis L on opposite lateral sides of the longitudinal axis. The platform P is supported by and connected to a chassis C that includes first (left) and second (right) spaced-apart main beams B1,B2 that extend parallel to each other and parallel to the longitudinal axis L on opposite sides of the longitudinal axis from the forward end FT to the rear end RT. Each beam B1,B2 typically defines an I-beam section or profile comprising an upper transverse flange F1 and a lower transverse flange F2 (FIG. 2B) connected by a vertical web BW. The beams can be steel or aluminum and are often fabricated by welding or otherwise abutting and welding together or otherwise connecting two separate T-shaped aluminum extrusions.
A kingpin K is located at the forward end FT of the trailer T′, centrally located between and connected to the beams B1,B2, and is adapted to be engaged by a fifth-wheel of an associated tractor/truck vehicle for towing the trailer T′. The rear end RT of the trailer includes at least one and typically at least two axle assemblies A connected to the chassis, e.g., to the lower flanges F2 of beams B1,B2. Each axle assembly A comprises at least one left and at least one right rotatable wheel and tire assemblies W for movably supporting the trailer T′ on a road or other surface. The trailer 7 further comprises a dolly assembly D, typically located axially between the kingpin K and an axial midpoint of the trailer T′. The dolly assembly D includes support feet DF that are selectively lowered to support the forward end FT of the trailer T′ when the kingpin is not connected to an associated tractor/truck (the dolly assembly D is omitted from the background of FIG. 2B for clarity).
The platform P comprises left and right side rails RL′,RR′ that delimit and define the opposite left and right lateral sides LP,RP of the platform P (and the overall trailer T′), respectively. These side rails RL′,RR′ are each typically defined as one-piece or monolithic extrusions of aluminum alloy such as 6061-T6 or 6005A-T6 or similar (often referred to herein simply as “aluminum”) having a profile such as that shown in FIG. 2B and that extend in one piece from the forward end FT to the rear end RT of the trailer T′ along the longitudinal axis L (the profiles of the side rails RL′,RR′ are typically mirror images of each other as shown herein). The side rails RL′,RR′ are often arched as shown in FIGS. 1A and 1B with an apex of the arch oriented upward and located between the forward and rear ends FT,RT.
The platform P, itself, comprises left, middle and right sections PL,PM,PR that each comprise one or more wood and/or metal longitudinally extending platform members PK, each of which extends longitudinally from the forward end FT to the rear end RT of the trailer T′, to define an upper cargo-supporting surface P1 of the platform P. Typically, the platform members PK each comprise a one-piece aluminum extrusion and/or a wooden plank or the like. In the illustrated embodiment, the platform members PK extend longitudinally between the forward and rear trailer ends FT,RT, but each platform member PK can alternatively extend transversely between and interconnect the left and right side rails RL′,RR′. In the illustrated trailer embodiment, the upper flange F1 of each beam B1,B2 also defines part of the platform surface P1, with the upper flange F1 of the first (left) beam B1 connected to both of the left and middle platform sections PL,PM and the upper flange F1 of the second (right) beam B2 connected to both of the right and middle platform sections PR,PM.
In the illustrated embodiment, to support the longitudinally extending platform members PK, the platform P of trailer T′ further comprises a plurality of transversely extending cross members CM located beneath the platform members PK at axially spaced intervals along the entire length of the trailer T′. The cross members CM are welded or otherwise connected to and extend between the left and right side rails RL,RR, passing through and typically welded to the beams B1,B2. In some cases the cross members CM comprise three separate “stub” cross member sections located respectively beneath and supporting the left, middle and right platform sections PL,PM,PR instead of a single cross member that passes through the beams B1,B2. These cross members CM can have a variety of shapes, e.g., I-beam, U-shaped, C-shaped, etc. and be defined from a variety of materials such as steel or aluminum, e.g., aluminum extrusions.
As shown in FIG. 3A, it is generally known in the art that the left and right side rails RL′,RR′ (only the left side rail RL is shown in FIG. 3A) are defined to include and/or have connected thereto a winch track WT adapted to be slidably engaged by an associated cargo strap winch W that contains a spooled length of a cargo strap CS for securing a load on the platform P. FIG. 3B shows an example of a right side rail RR′ having a similar structure as the left side rail RL′ including a winch track WT, but FIG. 3B shows that an associated flat hook retaining bracket K can additionally or alternatively be slidably engaged with the winch track WT. The flat hook retaining bracket K is adapted to receive and retain a flat hook (see flat hook FH in FIG. 7B) or other hook located at the distal end of a cargo strap CS.
The left and right side rails RL′,RR′ can alternatively be defined with or include a “double L” (LL) winch track WT2 as shown in FIG. 3C so that corresponding LL-style winches W and flat hook retaining brackets K can be slidably mated therewith. Each such side rail RL′,RR′ comprises a horizontal projecting lower wall LW′ comprising an outer end or tip LWE′. The outer end LWE′ is formed with a generally rectangular structure as defined between the parallel upper and lower parallel US′,LS' and a connecting wall CW′ that can be straight or slightly curved. Those of ordinary skill in the art will recognize that while a flat hook FH (FIG. 7B) or other hook can be engaged with the outer end LWE′ of the wall LW′, the outer end LWE′ would be loosely received in the flat hook recess HR and the flat hook FH would easily become detached from the outer end LWE′ when the cargo strap CS on which the flat hook is located is untensioned. Also, the flat hook FH would be free to pivot about the outer end LWE′ to a position where an undesirable bending moment MT′ exerted on the wall LW′ is increased.
A need has been identified for a new and improved trailer side rail structure that provides a superior structure and system for retaining a flat hook FH or other hook of a cargo strap CS, without requiring a separate bracket K to be affixed to the side rail and that protect the winch track WT1,WT2 of the side rail.